The major ancient Roman route Watling Street passed through the city, but was realigned in medieval times to bring trade to St Albans.

A large portion of the Roman city remains unexcavated, being now park and agricultural land, although due to ploughing on the privately owned agricultural half of the city a lot of damage has been done, as proven by parts of mosaic floors that have been found on the surface, and results of ground penetrating radar show outlines of buildings as smudges rather than clearly defined walls like those protected by the parkland.

The etymology is uncertain but the name has been reconstructed as *Uerulāmion, which would have a meaning like "[the tribe or settlement] of the broad hand" (Uerulāmos) in Brittonic.

The Roman settlement was granted the rank of municipium around AD 50, meaning its citizens had what were known as "Latin Rights", a lesser citizenship status than a colonia possessed.

Although recent results of GPR ( ground penetrating radar) have revealed more damage than originally thought has been done to most buildings, especially the north western part of the old Roman city.

An archaeological excavation in 1978, directed by Martin Biddle, failed to find Roman remains on the site of the medieval chapter house.

[9] David Nash Ford identifies the community as the Cair Mincip[10] ("Fort Municipium") listed by Nennius among the 28 cities of Britain in his History of the Britons.

[11] As late as the eighth century the Saxon inhabitants of St Albans nearby were aware of their ancient neighbour, which they knew alternatively as Verulamacæstir or, under what H. R. Loyn terms "their own hybrid", Vaeclingscæstir, "the fortress of the followers of Wæcla".

The modern city takes its name from Alban, either a citizen of Verulamium or a Roman soldier, who was condemned to death in the 3rd century for sheltering Amphibalus, a Christian.

Many items were found in formal excavations, but some, including the Verulamium Forum inscription and a coffin still containing a male skeleton, were unearthed nearby during building work.